lodash.curry

Currying Functions

Currying a function allows you to create new functions by partially applying some arguments. In this example, we curry the 'add' function and create a new function 'add5' that has the first argument fixed to 5.

const _ = require('lodash.curry');
const add = (a, b, c) => a + b + c;
const curriedAdd = _.curry(add);
const add5 = curriedAdd(5);
console.log(add5(10, 15)); // outputs 30

Associative Currying

Curried functions can be called with arguments one at a time (associative property). This means that the grouping of arguments is irrelevant; the result will be the same.

const _ = require('lodash.curry');
const add = (a, b, c) => a + b + c;
const curriedAdd = _.curry(add);
console.log(curriedAdd(5)(10)(15)); // outputs 30
console.log(curriedAdd(5, 10)(15)); // also outputs 30
console.log(curriedAdd(5)(10, 15)); // also outputs 30

Placeholder Arguments

Lodash.curry supports the use of placeholders. This allows you to skip arguments and provide them later. In this example, we create a function that has the first and third arguments fixed, and the second argument can be provided later.

const _ = require('lodash.curry');
const add = (a, b, c) => a + b + c;
const curriedAdd = _.curry(add);
const add5And = curriedAdd(5, _);
console.log(add5And(10, 15)); // outputs 30